Honeycomb reactor or heat exchanger mixer

Abstract: A honeycomb reactor or heat exchanger includes a honeycomb having a plurality of cells extending in parallel along a common direction from a first end to a second end thereof, with the cells being divided by walls , the honeycomb having one or more first passages formed within a first plurality of cells of the honeycomb , the first passages extending laterally from cell to cell within the honeycomb and being accessible via ports or holes in or through a side of the honeycomb . The honeycomb also as a plurality of second passages formed within a second plurality of cells within the honeycomb , the second passages each extending from first cell openings at the first end of the honeycomb to second cell openings at the second end of the honeycomb . The second passages each describe at least one S-bend beginning at the first end of the monolith and extending to the second end and there bending back to the first end and there bending back again to the second end .

BACKGROUND

This application claims the benefit of priority of U.S. Provisional Application Ser. No. 61/182,757 filed on May 31, 2009.

SUMMARY

The present disclosure relates to honeycomb reactors or heat exchangers, and particularly to such honeycomb reactors or heat exchangers providing enhanced mixing of fluids passing therethrough, and to methods for forming such devices.

DETAILED DESCRIPTION

According to one embodiment of the present disclosure, a honeycomb reactor or heat exchanger includes a honeycomb having a plurality of cells , extending in parallel along a common direction from a first end to a second end thereof, with the cells being divided by walls , the honeycomb having one or more first passages formed within a first plurality of cells of the honeycomb , the first passages extending laterally from cell to cell within the honeycomb and being accessible via ports or holes in or through a side of the honeycomb . The honeycomb also as a plurality of second passages formed within a second plurality of cells within the honeycomb , the second passages each extending from first cell openings at the first end of the honeycomb to second cell openings at the second end of the honeycomb . The second passages each describe at least one S-bend beginning at the first end of the monolith and extending to the second end and there bending back to the first end and there bending back again to the second end .

Other features and advantages of the present invention will be apparent from the figures and following description and claims.

Various techniques for fabricating low-cost continuous flow chemical reactors or heat exchangers based on honeycomb monolith technology have been presented by the present inventor and/or his associates, such as those disclosed in PCT Publication No. WO2008121390, for example, assigned to the present assignee.

As shown herein in the perspective view of and in the partial cross section of , in reactors or heat exchangers of the type generally utilized in the context of the present disclosure, a fluid flows along one or more first paths or passages defined within a set of typically millimeter-scale channels in a honeycomb monolith , which channels are closed, generally at both ends, by individual plugs or plugging material . Selected walls between channels are lowered as seen in the cross-section of (where every other wall in the cross-section is lowered).

A gap is left between plugs or continuous plugging material and the top/bottom of the lowered walls . This can allow for a long, relatively large volume serpentine first passage to be formed in the honeycomb monolith as seen in .

The first passage may be accessed via access ports or holes in the sides of the honeycomb monolith . Typically, heat exchange fluid is flowed parallel to the extrusion direction through the many open millimeter-scale channels .

If the lowered walls are lowered nearly to the respective far end of the body by means of deep plunge machining, a high-aspect ratio first passage can be produced, which may be accessed by from multiple ports , as shown in the cross-section of . Variations between the two extremes of may also be used, such as a serpentine passage that follows more than one cell of the honeycomb monolith at a time, in parallel. Such passages are disclosed in PCT Publication No. WO2008121390, mentioned above.

Plugs or continuous plugging material can take various forms, including sintered plugs or plugging material typically assuming a shape somewhat like that shown at the bottom of , or other forms, including epoxy or other polymer material and other materials that result in more or less square plugs or plugging material as shown at the top of .

The shape of the one or more first paths or passages in the plane perpendicular to the direction of the cells of the honeycomb monolith may take various forms, as shown in the plan views of . As shown in and as an alternative to a straight line shape as shown in , the one or more first paths or passages may have a serpentine shape in the plane perpendicular to the cells of the honeycomb monolith . As an additional alternative, a branching shape may be used as shown in , in which a first passage divides within the extruded structure into many sub-passages, then re-joins before exiting the structure . As another additional alternative, multiple first passages may be defined through the honeycomb monolith as shown in .

As noted above, typically, heat exchange fluid is flowed parallel to the extrusion direction through the many open millimeter-scale channels . But there are instances in which reactant fluid or reactant-containing fluid may beneficially be flowed in short paths like those of the open channels of . Particularly where high flow rates with high surface area exposure and low pressure drop are desired, the extreme parallelism achievable in the channels is desirable, and the one or more first passages may be used for thermal exchange. Where a high rate of thermal exchange is desired, high aspect ratio channels as in may be applied in a configuration like that of .

The present disclosure adds the possibility of providing mixing within this high throughput, high surface area processing environment. Specifically, a honeycomb reactor or heat exchanger for providing enhanced mixing of fluids includes may be understood with reference to the plan view of a reactor within a honeycomb as shown in , with reference to . The honeycomb includes a plurality of cells , extending in parallel along a common direction from a first end to a second end thereof, with the cells divided by walls .

The reactor includes one or more first passages formed within a first plurality of cells of the honeycomb and extending laterally from cell to cell within the honeycomb . The one or more first passages are accessible via ports or holes in or through a side of the honeycomb , as shown in .

The reactor further includes a plurality of second passages formed within a second plurality of cells within the honeycomb . Two different embodiments of second passages are shown in cross-sectional view in , with the second passage of having a single S-bend and the second passage of having one and one-half S-bends therein. The type of second passage shown in corresponds to the type of second passages in the reactor of

The second passages each extend from first cell openings at the first end of the honeycomb to second cell openings at the second end of the honeycomb . According to the present disclosure for reactors of the type disclosed herein, the second passages each describe at least one S-bend beginning at the first end of the monolith and extending to the second end and there bending back to the first end and there bending back again to the second end , as with the second passage of and the second passages of the reactor of .

Second passages having higher numbers of S-bends may also be used, such as two or more, for example. Further, the second passages need not, although they may, always be in a single respective plane. Neither of the second passages shown in plan view in lie in a single respective plane, for example.

For many applications, it is desirable that the first cell openings are distributed across the first end of the honeycomb of the reactor in a two-dimensional distribution, as shown in .

The honeycomb desirably comprises glass, glass-ceramic, or ceramic, but other materials may also be employed as desired.

Reactors according to the present disclosure may be beneficially used in more than one mode. As one mode, a reactant or reactant-containing fluid may be flowed in the one or more first passages while a heat exchanging fluid is flowed in the second passages . As a second mode, a reactant or reactant-containing fluid may be flowed in the second passages while a heat exchanging fluid is flowed in the one or more first passages . As a third mode, a first reactant or reactant-containing fluid may be flowed in the one or more first passages while a second reactant or reactant-containing fluid is flowed in the second passages .

The reactors of the present disclosure may also be beneficially employed in a multistage reactor as shown in schematic perspective view in . the multistage reactor includes a plurality of reactors A-D of the type according to the present disclosure, arranged in an order such that a fluid flowing out from the second passages of at least one of the plurality of reactors A-C flows directly into the second passages of the next of the plurality of reactors B-D. Desirably, the number of S-bends of the second passages varies from at least one of the plurality of reactors A-C to the next B-D, and the height H of the plurality of reactors A-D may also vary from at least one of the plurality of reactors A-C to the next B-D. This allows for flexible customization of the heat exchange and mixing needs of a reaction process within the fluid .

Not as a limiting features, but as one potential benefit, the methods and devices of the present disclosure can provide for almost any desired degree of mixing within an easily manufactured, very high flow parallel channel (the second passages ). By utilizing high flow rates and or by restricting the height H of the honeycombs , relatively fast mixing can be achieved.